Age has been the risk fact most consistently associated with the development of tardive dyskinesia (TD). Increased rates of prevalence, severity and persistence of TD are associated with increasing age. Interpretation of true prevalence rates is complicates by reports of idiopathic spontaneously occurring movement disorders in the elderly. Additionally, elderly persons suffering from various medical conditions which may predispose them to develop drug-induced or spontaneous movement disorders. To evaluate the incidence, outcome of and vulnerability to movement disorders in the elderly, 407 patient over the age of 55 will be evaluated prospectively while receiving neuroleptic treatment. The patients will be starting on neuroleptics for the first time at study entry. After an initial baseline assessment, patients will be reexamined every three months for four years. Assessments will include examinations for TD and extrapyramidal side effects, psychiatric symptomatology and mental status and ongoing medication history. Medication will be withdrawn every six months to assess convert TD. Patients meeting criteria for abnormal movement case identification will receive a medical and neurological work-up to identity possible alternative causes of the movement disorder, and continue in follow-up to assess the course and outcome of their abnormal movements. Patients who show "spontaneous" dyskinesias at their baseline examination will also be followed prospectively to study the course of their abnormal movements over time and in relation to medication.